Bullet, bullet jacket and methods of making

ABSTRACT

A bullet, bullet jacket, and method of making the bullet and bullet jacket. The bullet jacket comprises a predominantly copper outer shell and a predominantly zinc lining. The bullet comprises the bullet jacket and a bullet core. The bullet jacket is made by forming a predominantly copper sheet and a predominantly zinc sheet. The two sheets are then adhered to one another by cladding or roll bonding, and shaped such that they can fully encase a bullet core. The bullet is then made by using conventional means to seat and enclose the bullet core within the bullet jacket of the present invention.

FIELD OF THE INVENTION

[0001] The present invention relates generally to small firearmmunitions (“bullets”), and more particularly, to a casing (“jacket”)that surrounds a bullet, and a method for making the same.

BACKGROUND OF THE INVENTION

[0002] Bullets with a copper jacket and lead core (“standard bullets”)are a nearly universal standard in both civilian and militaryapplications. For example, it has been estimated that one manufacturerof small arms ammunition may distribute as many as 5 million standardbullets annually for civilian use. Additionally, the United Statesmilitary has used standard bullets for decades.

[0003] Unfortunately, the use of standard bullets give rise tosignificant environmental problems. Standard bullets are, in fact,responsible for two major types of environmental hazards. Because 90-95%of the total weight of standard bullets is lead, these bullets have thepotential to introduce large quantities of lead toxin into ourenvironment. First, lead vapors and lead dust caused by the use ofstandard lead bullets in indoor shooting ranges are a significant hazardto employees and users of such ranges. Lead dust and vapors are releasedfrom bullets striking target back-stops. The small particles of leadreleased with each impact eventually permeate the air of these confinedareas and may eventually cause serious health difficulties, while thepresence of a jacket over a lead core bullet helps to reduce the hazardsrelated to lead dust, any new bullet designs should consider thisenvironmental hazard in the design.

[0004] In situations where a large number of standard bullets are firedoutdoors, the lead presents a second environmental hazard. Bullets areoften left in large quantities on the grounds of practice ranges and onbattle fields. Despite the copper jacket surrounding the lead core ofstandard bullets, these bullets corrode. The lead from standard bulletsleaches into the soil, eventually contaminating the soil, rain waterrun-off and ground water. The cost of hazardous waste clean-up of thelead is often significant—the cost of such a clean-up is, therefore,prohibitive for operators of outdoor shooting ranges. Consequently, theowners of such ranges do not voluntarily engage in a clean-up operation.Thus, lead contamination of the environment by standard bullets left onsuch ranges merely continues to grow.

[0005] In view of the environmental hazards resulting from firing anddiscarding standard bullets, it is desirable to develop a bullet whicheliminates or reduces these hazards. One solution to the environmentalhazards is to design bullets that do not contain a lead core. However,the non-lead core bullets present other problems. Such bullets oftenhave a smaller mass than standard bullets. This difference in mass mayresult in a bullet of less stopping power. In other words, a bulletdesigned without a lead core may fail in its essential purpose.Furthermore, the small mass of non-lead bullets often leads tosignificant ricochet problems. A bullet having a weight of approximately50% of a standard bullet may strike a target and ricochet as far back asto the shooter. Such ricochets present a great danger to targetshooters, especially those who shoot in an indoor range. New bulletdesigns have been developed to address these problems. However,manufacturing new bullet designs requires significant expenditures forthe design and construction of new manufacturing tools to accommodatethe new bullet designs. Therefore, it is desired to create a bullet thathas dimensions and capabilities very similar to those of standardbullets.

[0006] The manufacture and use of tungsten bullets is illustrative ofadditional problems presented by removing lead from bullet designs.Tungsten bullets do not create dusts or vapors when fired, and are inertwhen stored on the ground. However, tungsten is a very expensivematerial. The manufacture of tungsten bullets may cost as much as 16times more than the cost of manufacture of standard bullets having atraditional lead core and copper jacket. Additionally, there is littleinformation regarding the effect of tungsten in a wound. It is known,however, that tungsten powder produces tissue necrosis and thatconventional x-ray equipment cannot locate tungsten within a human body.Therefore, a wound created by a tungsten bullet is difficult to treat.Thus, it is desired to produce a bullet, which does not present suchproblems related to diagnosis and treatment.

[0007] U.S. Pat. No. 6,095,052, issued Aug. 1, 2000 also results analternative to lead core bullets. However, the bullet of this patentalso fails to be a complete solution. The invention of this patentinvolves the attachment of zinc foil to a lead sheet. This sheet andfoil are rolled and pressure formed into a bullet having generallyhelical layers of lead sheet and zinc foil. This method provides a zinclayer over the lead core of a bullet and may be effective in preventinga lead contained in a standard bullet from leaching into soil or groundwater. However, the process for making such a bullet is difficult andexpensive. Given the high volume of bullets produced by even a singlemanufacturer, adding complexity to the manufacturing process is likelyto have a significant impact on the cost of producing bullets and, bynecessary implication, on the cost of purchasing bullets. Therefore, itis desired to provide a bullet which is environmentally friendly butwhich is reasonable in cost of materials and manufacture.

SUMMARY OF THE INVENTION

[0008] The advantages of the present invention are achieved by providingan environmentally safe bullet that maintains the performancecharacteristics of standard bullets. The bullet jacket of the presentinvention comprises a predominantly copper outer layer and apredominantly zinc lining that is adjacent to the lead core of a bullet.The bullet jacket is formed by roll bonding or cladding a predominantlyzinc layer to a predominantly copper layer and shaping, by conventionalmeans, the bimetallic combination into a bullet jacket. In oneembodiment, the predominantly zinc layer of the bullet jacket should notexceed about 30% by weight of the weight bullet jacket, and thepredominantly copper layer should not be less than about 70% by weightof the weight bullet jacket. Significant deviation from these guidelinesmay adversely affect the performance of a bullet employing the bulletjacket.

[0009] The bullet of the present invention comprises a bullet jacketformed as described above, and further comprises a substantially leadbullet core. Conventional means for seating and encasing lead bulletcore within copper jackets are used to seat the bullet cores of thepresent invention within the bullet jacket of the present invention. Abullet thus made has several advantages over standard bullets and overbullets containing no lead at all.

[0010] As previously discussed, the lead from standard bullets leftoutside after being fired reacts with the environment causingsignificant contamination to soil and water. However, when bullets ofthe present invention are similarly discarded, the zinc lining of thepresent bullet jacket acts like a battery anode and prevents the leadcore from reacting with the environment, thereby preventingenvironmental contamination of soil and water. As previously discussed,the presence of a jacket over the lead core, also helps to reduce thelevels of lead dust occurring upon impact.

[0011] The fact that a bullet according to the present invention isenvironmentally safe while continuing to use a lead core providesseveral advantages over other bullets. First, because the bulletcontains a lead core, it maintains the mass and shape of a standardbullet. Consequently, the performance characteristics of the presentlydesigned bullet, in terms of stopping power and flight, do not differsignificantly from standard bullets. Bullets having the present bulletjacket therefore do not require any significant design changes or thecollateral expenses associated with new designs that leadless bulletsoften require. Further, because the lead cores of the present inventionare of the type normally used in standard bullets, there is norequirement to design and manufacture unique bullet cores. Therefore,the additional expenses in design and manufacture that would benecessitated by unique bullet cores are avoided by the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 shows a cross-sectional view of one embodiment of thebullet of the present invention.

[0013]FIG. 2 shows a cross-sectional view of a second embodiment of thebullet of the present invention.

DETAILED DESCRIPTION OF INVENTION

[0014] Referring now to FIG. 1, there is shown a cross-sectional view ofone embodiment of the bullet according to the present invention. In thisembodiment, the bullet 50 comprises bullet jacket 10 and bullet core 40.Bullet jacket 10 is comprised of a predominantly zinc layer 20 and apredominantly copper layer 30 adhered to zinc layer 20. Layers 20 and 30of the bullet jacket 10 are formed into a shape appropriate for thereceipt of bullet core 40, such that when bullet core 40 is placedtherein predominantly zinc layer 20 is adjacent to the bullet core 40.The size of bullet jacket 10 is chosen to be large enough to fullyencase bullet core 40, regardless of the size of the bullet core 40.

[0015] In this embodiment, bullet core 40 preferably consistsessentially of lead. However, those skilled in the art will recognizethat the bullet core 40 may include a blend of metals, which can includevarious amount of lead. Such a blend will allow for the manufacture ofbullets of varying grain weights for use with a range of weapons. Bulletcore 40 further comprises substantially conical shape and can be anyconventional lead bullet core shape. It will be appreciated that byaccommodating a variety of lead bullet cores, bullet jacket 10 of thepresent invention can be easily used with standard mass produced leadbullet cores. Thus, implementing the present invention in themanufacture of bullet jackets does not require the significant andexpensive changes to current manufacturing processes used to producebullets. Instead, one may merely replace the standard copper bulletjackets with bullet jackets made according to the present invention.

[0016] One skilled in the art will also recognize that bullet jacket 10of the present invention easily accommodates bullet core 40 which hasbeen manufactured by generally understood means and which conforms tothe dimensions, mass and material composition of a conventional bulletcore.

[0017] As stated previously, bullet jacket 10 of the present inventionis comprised a predominantly zinc layer 20 and a predominantly copperlayer 30. To fall within the scope of the present invention, the zinclayer 20 may be comprised of other alloys, such as aluminum, but thezinc in zinc layer 20 should comprise at least about 97% by weight ofthe total weight of zinc layer 20. Similarly, copper layer 30 may becomprised of other alloys, such as tin, but that copper in copper layer30 should comprise at least about 85% by weight of the total weight ofcopper layer 30.

[0018] In testing bullets which employ bullet jacket 10, it has beenobserved that predominantly zinc layer 20 should generally not comprisemore than about 30% by weight of the total weight of bullet jacket 10,and predominantly copper layer 30 should generally comprise less thanabout 70% by weight of the total weight of bullet jacket 10. Significantdeviation from these guidelines could adversely affect the performanceof a bullet manufactured according to the present invention.

[0019] It will be appreciated by one skilled in the art thatpredominantly zinc layer 20 and predominantly copper layer 30 may beformed into sheets by conventional manufacturing means such as castingand rolling. Generally, predominantly zinc layer 20 and predominantlycopper layer 30 must be directly adhered to one another such that thetwo layers will not separate during the manufacture of bullet jacket 10,during the manufacture or use of a bullet made according to the presentinvention, or during firing or projection of such a bullet.

[0020] In one embodiment of bullet jacket 10, predominantly zinc layer20 is roll-bonded to predominantly copper layer 30. In yet anotherembodiment of bullet jacket 10, the layer of predominantly zinc 20 iscladded to the layer of predominantly copper 30.

[0021] It will be appreciated by one of skill in the art that any methodof directly adhering predominantly zinc layer 20 to predominantly copperlayer 30 can be used as long as the method employed results inprevention of separation of layers 20 and 30 from each other during themanufacturing process or loading or firing of a bullet manufacturedaccording to the present invention.

[0022] As shown in FIG. 1, bullet jacket 10 is formed into a shape whichencases bullet core 40, such that the predominantly zinc layer 20 isadjacent to bullet core 40. In other words, bullet jacket 10 is shapedfor receipt of bullet core 40, with predominantly zinc layer 20surrounding and engaging the shape of bullet core 40.

[0023] In bullet 50 according to the present invention, bullet core 40preferably consists essentially of lead or lead alloys. It will beappreciated that the bullet jacket of the present invention provides aprotective covering of zinc to prevent the introduction of lead into theenvironment from discarded lead bullets. Bullet jacket 10 encases entirebullet core 40. Specifically, predominantly zinc layer 20 rests between,and in direct contact with bullet core 40 and predominantly copper layer30. When bullet 50 is exposed to the environment, whether before, duringor after firing, it is surrounded by bullet jacket 10 of the presentinvention in the same way that a standard copper jacket surrounds astandard bullet. However, bullet jacket 10 includes predominantly zinclayer 20 directly adjacent to the bullet core 40 which acts as asacrificial anode when bullet 50 is, for example, left outdoors afterhaving been fired. Thus, bullet 50 of the present invention prevents theleaching of lead into the environment by bullets left on the groundoutside after firing as described in more detail below.

[0024] Predominantly zinc layer 20 in bullet 50 acts like the anode in abattery by taking on additional electrons. Conversely, predominantlycopper layer 30 acts like the cathode in a battery by giving upelectrons. When bullet 50 is left outside, the environment chemicallyreacts with copper layer 30 and zinc layer 20 rather than bullet core40. In this manner, bullet jacket 10 prevents lead from bullet core 40from leaking into and contaminating outdoor soil and water.

[0025] Another advantage realized by bullet 50 is that it mayaccommodate standard mass produced lead bullet cores. By doing so,bullet 50 is able to maintain the mass and dimensions of standardbullets of various calibers. Consequently, bullet 50 is able to maintainthe expected performance characteristics of standard bullets.Maintaining these performance characteristics eliminates the need fornew bullet exterior designs or new gun designs to recreate theperformance characteristics of a standard bullet. For example, 90% to95% of the mass of a standard bullet typically comes from lead. Abullet's “stopping power” is directly related to its mass. A bullet madeaccording to the present design is able to maintain the use of a denselead core and thus a relatively high mass and good stopping power. Abullet design which sought to protect the environment by removing leadfrom the bullets would require extensive efforts to design bullets withthe same stopping power and other performance characteristics ofstandard bullets. In addition, a bullet so designed requires new weaponsdesigns to accommodate such a bullet. To the contrary, bullet 50 of thepresent design addresses environmental issues without sacrificing bulletperformance or necessitating the expenses associated with redesigningbullets or guns, or the tools that produce both products.

[0026] The present invention also includes a method of making the bulletjacket 10. The first step in the method of making bullet jacket 10 is toform the layer of predominantly zinc 20. As stated previously, oneskilled in the art will understand that this step can be accomplished byany generally understood means such as rolling. The second step inmaking the bullet jacket 10 is to use similar methods to form the layerof predominantly copper 30.

[0027] The next step in the method of making bullet jacket 10 is toadhere the layer of predominantly zinc 20 directly to the layer ofpredominantly copper 30. As previously discussed, this adherence step isaccomplished by roll-bonding, cladding, or other methods well known inthe art. It will be appreciated by one skilled in the art that the oneadvantage of the use of either roll-bonding or cladding is that layers20 and 30 will not separate during the manufacture or use of a bulletemploying bullet jacket 10. Another advantage of these adherence methodsis that roll-bonding and cladding are well known methods of bonding onemetal directly to the other and can be accomplished without greatexpense. However, other means of adhering sheets of copper and zinc toeach other, such as adhesive laminating, are contemplated to be withinthe scope of the invention.

[0028] Adhering predominantly zinc layer 20 to predominantly copperlayer 30 results in formation of a bimetallic strip or sheet. In orderto avoid adversely affecting the performance of a bullet comprising thebullet jacket 10 of the present invention, it is recommended no morethan about 30% by weight of this strip or sheet should be composed ofpredominantly zinc layer 20 and no less than about 70% by weight of thisstrip or sheet should be composed of predominantly copper layer 30.

[0029] The method of making the bullet jacket 10 next requires shapingthe combined layers 20 and 30 into a form capable of receiving thebullet core 40, wherein the layer of predominantly zinc 20 is adjacentto bullet core 40. This step may be accomplished by any conventionalmeans such as stamping and drawing, whereby adhered layers 20 and 30 aremade to encase the entire bullet core 40 and the layer of predominantlyzinc will be adjacent to the bullet core 40.

[0030] The present invention also includes a method of making bullet 50.The first step is to determine the caliber of bullet one intends tomake. The dimensions of bullet jacket 10 will depend on this decision.The appropriate bullet core 40 is chosen to conform with the caliber ofbullet desired. The next step in the method of making bullet 50 is toform predominantly zinc layer 20 and predominantly copper layer 30, aspreviously described herein. The next step in making bullet 50 is toadhere predominantly zinc layer 20 directly to predominantly copperlayer 30 as previously described herein.

[0031] The method of making bullet 50 next requires shaping the combinedlayers 20 and 30 into a form capable of receiving the bullet core 40,wherein the layer of predominantly zinc 20 will be adjacent to thebullet core 40 as previously described herein.

[0032] The final step in making bullet 50 is to introduce bullet core 40into the bullet jacket 10. One method of accomplishing this is to placebullet core 40 within bullet jacket 10 such that one end of bullet core40 rests on the interior base of bullet jacket 10, and the sides ofbullet core 40 rest against the interior sides of bullet jacket 10. Theopposite end of bullet core 40 is recessed below the open end of bulletjacket 10. Bullet core 40 is pressed into bullet jacket 10 and bulletjacket 10 is made to enclose bullet core 40 using a commonly available“bullet press.” One skilled in the art will understand that that thisstep can be accomplished by any means currently employed to enclosebullet cores with copper bullet jackets, and that the description aboveis used merely to illustrate one such means.

[0033] It will be appreciated by those of skill in the art that theindividual steps required to make the bullet jacket and bullet of thepresent invention are conventional. Thus, a manufacturer does not needto learn new processes for such individual steps, nor is a significantinvestment in new metal working equipment required. Therefore, themethods of the present invention are relatively inexpensive anduncomplicated when compared to methods required to make prior artalternatives to standard bullets. Further, the materials required arereadily available—a big plus in keeping material costs reasonable.

[0034] Referring now to FIG. 2, there is shown a second embodiment ofthe bullet according to the present invention. In this embodiment,bullet 60 comprises bullet core 40 and bullet jacket 70. As in theembodiment FIG. 1, bullet core 40 of FIG. 2 is comprised primarily oflead or lead alloy and is conical in shape, and bullet jacket 70 iscomprised of copper (or copper alloy) and zinc (or zinc alloy). Bulletjacket 70 is comprised of first predominantly zinc layer 71 and firstpredominantly copper layer 72 surrounding the majority of bullet core40, and of second predominantly zinc layer 73 and second predominantlycopper layer 74 over the end cap portion of bullet core 40. Bulletjacket 70 is made according to the same method described above inassociation with bullet 50 of FIG. 1. To make bullet 60, bullet jacket70 is formed into two pieces (perhaps from the same adhered sheets ofcopper and zinc) and one piece is formed for receipt of bullet core 40and another piece formed to connect the end cap. Those two pieces arethen adhered to each other by means well known in the art, such aspressing.

[0035] Having described the present inventions in terms of their variousembodiments and as illustrated by the accompanying figures, it will berecognized by those skilled in the art that certain changes can be madeto the specific embodiments discussed herein without changing the mannerin which the components or steps of the present invention function orachieve their intended result. All such changes are intended to fallwithin the spirit and scope of the following claims.

I claim:
 1. A bullet jacket, comprising: a layer of predominantly zincand a layer of predominantly copper adhered to the layer ofpredominantly zinc, with the adhered layers formed into a shapeappropriate for the receipt of a bullet core such that when the bulletcore is placed in the formed shape the predominantly zinc layer isadjacent to the bullet core.
 2. The bullet jacket of claim 1, whereinthe predominantly zinc layer is roll-bonded to the predominantly copperlayer.
 3. The bullet of jacket claim 1, wherein the predominantly zinclayer is cladded to the predominantly copper layer.
 4. The bullet jacketof claim 1, wherein the predominantly zinc layer comprises no more thanabout maximum of 30% by weight of the weight of the bullet jacket. 5.The bullet jacket of claim 1, wherein the predominantly copper layercomprises no less than about 70% by weight of the weight of the bulletjacket.
 6. A bullet jacket, comprising: a plurality of bimetallic sheetscomprising layer of predominantly zinc and a layer of predominantlycopper adhered to the layer of predominantly zinc, with the adheredlayers formed into a plurality of shapes appropriate for surrounding abullet core such that when the bullet core is placed in the plurality ofbimetallic sheets the predominantly zinc layer of each bi-metallic sheetis adjacent to the bullet core.
 7. The bullet jacket of claim 6, whereinthe predominantly zinc layer is roll-bonded to the predominantly copperlayer.
 8. The bullet of jacket claim 6, wherein the predominantly zinclayer is cladded to the predominantly copper layer.
 9. The bullet jacketof claim 6, wherein the predominantly zinc layer comprises no more thanabout maximum of 30% by weight of the weight of the bullet jacket. 10.The bullet jacket of claim 6, wherein the predominantly copper layercomprises no less than about 70% by weight of the weight of the bulletjacket.
 11. A bullet, comprising: a bullet core having a core shape, alayer of predominantly zinc and a layer of predominantly copper adheredto the layer of predominantly zinc, with the adhered layers surroundingthe bullet core such that the predominantly zinc layer is adjacent tothe bullet core.
 12. The bullet of claim 11, wherein the bullet coreconsists essentially of lead.
 13. The bullet of claim 11, wherein thepredominantly zinc layer of the bullet jacket is roll-bonded to thepredominantly copper layer.
 14. The bullet of claim 12, wherein thepredominantly zinc layer of the bullet jacket is roll-bonded to thepredominately copper layer.
 15. The bullet of claim 11, wherein thepredominantly zinc layer of the bullet jacket is cladded to thepredominantly copper layer.
 16. The bullet of claim 12, wherein thepredominately zinc layer of the bullet jacket is cladded to thepredominantly copper layer.
 17. The bullet of claim 11, wherein thepredominantly zinc layer comprises no more than about 30% by weight ofthe weight of the bullet jacket.
 18. The bullet of claim 12, wherein thepredominantly zinc layer comprises no more than about 30% by weight ofthe weight of the bullet jacket.
 19. The bullet of claim 11, wherein thepredominantly copper layer comprises no less than about 70% by weight ofthe weight of the bullet jacket.
 20. The bullet of claim 12, wherein thepredominantly copper layer comprises no less than about 70% by weight ofthe weight of the bullet jacket.
 21. A method of making a bullet jacket,comprising the steps of: forming a predominantly zinc layer; forming apredominantly copper layer; adhering the predominantly zinc layer to thepredominantly copper layer; and shaping the adhered layers into a formcapable of receiving a bullet core such that, when a bullet core isplaced in the formed shaped, the predominantly zinc layer is adjacent tothe bullet core.
 22. The method of making the bullet jacket of claim 21,wherein the step of adhering the predominantly zinc layer to thepredominantly copper layer comprises roll-bonding the predominantly zinclayer to the predominantly copper layer.
 23. The method of making thebullet jacket of claim 21, wherein the step of adhering thepredominantly zinc layer to the predominantly copper layer comprisescladding the predominantly zinc layer to the predominantly copper layer.24. A method of making a bullet, comprising the steps of: providing ashaped bullet core; forming a predominantly zinc layer; forming apredominantly copper layer; adhering the predominantly zinc layer to thepredominantly copper layer; shaping the adhered layers to receive thebullet core such that the predominantly zinc layer is adjacent to thebullet core; placing the bullet core within the shaped form; seating thebullet core within the formed shape; and enclosing the bullet jacketaround the bullet core.
 25. The method of making the bullet of claim 24,wherein the step of adhering said predominantly zinc layer to saidpredominantly copper layer comprises roll-bonding the predominantly zinclayer to the predominantly copper layer.
 26. The method of making thebullet of claim 24, wherein the step of adhering the predominantly zinclayer to the predominantly copper layer comprises cladding thepredominantly zinc layer to the predominantly copper layer.